Luer lock connections are known, with which the threaded sleeve surrounding the Luer cone is rotatable relative to the Luer cone about its longitudinal axis. This design may be intended and e.g. used, to be able to fix a female counter-piece on the Luer cone by rotating the threaded sleeve, without having to rotate the Luer cone. A rotation of the threaded sleeve may be unavoidable if the Luer cone and the threaded sleeve consist of different materials and are put or stuck onto one another, as is common e.g. with glass syringes.
The problem with this design is that the connection may easily come undone, in particular if moisture or lubricant such as e.g. silicone oil gets onto the Luer cone or into the thread of the threaded sleeve, or particularly smooth materials such as e.g. PTFE are used.